This invention relates to gun barrels and more particularly to gun barrels for automatic weapons.
Permanent barrel distortion or bending in the M60 E3 machine gun is attributed to two causes. The first cause, that of thermal mismatch between barrel and gas cylinder and other cause is permanent bending due to barrel whip. The barrel whip is perceived to arise from moments or torques placed on the barrel during gun firing. The present barrel is a thin steel barrel and during the operation the temperature reaches some 1200.degree. F. The yield strength of the barrel steel is estimated to be 50,000 PSI at room temperature and 0.1% offset yield strength at 1300.degree. F. is less than 10,000 PSI. Under these conditions, the barrel bends during service. To alleviate this problem, industry began to design a thick barrel which increased its weight almost three fold, resulting in a large weight penalty.